Siemens 7SJ85 - Stage with Negative-Sequence Voltage; Description; Application and Setting Notes

Stage with Negative-Sequence Voltage
Description
Logic of a Stage
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Figure 6-189
Logic Diagram of the Stage: Overvoltage Protection with Negative-Sequence Voltage
Method of Measurement
The stage uses the average value of the negative-sequence voltage, which is calculated from the function
block General Functionality. For more information, refer to chapter 6.26.3.1 Description.
Blocking the Stage
In case of blocking, the picked up function is reset. The following blocking option is available for the function:
•
From an external or internal source via the binary input signal
>Block stage
Application and Setting Notes
Parameter: Threshold
•
Default setting (_:271:3) Threshold = 5.800 V
The parameter Threshold is set according to the definition of the negative-sequence system.
Specify the Threshold (pickup threshold) for the specific application.
The secondary voltage of the voltage transformer can be used if the voltage transformer is adapted to the
rated voltage. The value of the 10 % negative-sequence voltage at a 100 V rated secondary voltage is:
100 V / 1.73 * 0.1 = 5.77 V
6.26.4
6.26.4.1
6.26.4.2
Protection and Automation Functions
6.26 Overvoltage Protection with Negative-Sequence Voltage
SIPROTEC 5, Overcurrent Protection, Manual 717
C53000-G5040-C017-8, Edition 07.2017